Proof of Theorem ralpr
| Step | Hyp | Ref
| Expression |
| 1 | | df-ral 1652 |
. 2
⊢ (∀x ∈ {A, B}φ ↔
∀x(x ∈ {A, B} → φ)) |
| 2 | | visset 1816 |
. . . . . 6
⊢ x ∈
V |
| 3 | 2 | elpr 2428 |
. . . . 5
⊢ (x ∈ {A, B} ↔
(x = A
⋁ x =
B)) |
| 4 | 3 | imbi1i 186 |
. . . 4
⊢ ((x ∈ {A, B} →
φ) ↔ ((x = A ⋁ x = B) → φ)) |
| 5 | | jaob 424 |
. . . 4
⊢ (((x = A ⋁ x = B) → φ)
↔ ((x = A → φ)
⋀ (x =
B → φ))) |
| 6 | 4, 5 | bitr 173 |
. . 3
⊢ ((x ∈ {A, B} →
φ) ↔ ((x = A →
φ) ⋀
(x = B
→ φ))) |
| 7 | 6 | albii 1001 |
. 2
⊢ (∀x(x ∈ {A, B} →
φ) ↔ ∀x((x = A →
φ) ⋀
(x = B
→ φ))) |
| 8 | | 19.26 1069 |
. . 3
⊢ (∀x((x = A →
φ) ⋀
(x = B
→ φ)) ↔ (∀x(x = A →
φ) ⋀
∀x(x = B → φ))) |
| 9 | | ralpr.1 |
. . . . 5
⊢ A ∈
V |
| 10 | 9 | sbc6 1960 |
. . . 4
⊢ ([A / x]φ ↔ ∀x(x = A →
φ)) |
| 11 | | ralpr.2 |
. . . . 5
⊢ B ∈
V |
| 12 | 11 | sbc6 1960 |
. . . 4
⊢ ([B / x]φ ↔ ∀x(x = B →
φ)) |
| 13 | 10, 12 | anbi12i 484 |
. . 3
⊢ (([A / x]φ ⋀
[B / x]φ) ↔
(∀x(x = A → φ)
⋀ ∀x(x = B →
φ))) |
| 14 | 8, 13 | bitr4 176 |
. 2
⊢ (∀x((x = A →
φ) ⋀
(x = B
→ φ)) ↔ ([A / x]φ ⋀
[B / x]φ)) |
| 15 | 1, 7, 14 | 3bitr 177 |
1
⊢ (∀x ∈ {A, B}φ ↔
([A / x]φ ⋀ [B /
x]φ)) |